I bet it was developed as a device in comics and may not have been typographic originally, but instead used skull-and-crossbones, stars, etc. The visual nature of the practice just doesn't seem to fit historically with typographic practice.

"-- Blurgits, plewds, maledicta and speed lines: Just a few of the terms that define the stuff you see in comic books all the time.

Everything has a name -- the left arm of chair has a different name than the right side of a chair, to a carpenter. And to comic-book people, the various things we do, use and see have names.

Maledicta: It's Latin for roughly, "bad words." It refers to *^%&$#@!! Every time Sarge Snorkel uses symbology for "bad words," it's maledicta. Not the same as Sgt. Fury, who uses substitute words -- "Lantern-jawed, gold-brickin', pink-eyed son of a bob-tailed hyena" isn't maledicta. That's "euphemism." Maledicta is lightning bolts, death's-heads, and crapola from the top line of the keyboard to indicate bad words. Bad words: maledicta. (Mal=bad, as in malfeasance. Dicta, as in words, as in dictionary.)

Plewds: Great big sweat beads that leap off a character's head to show anxiety. Outside of Beetle Bailey, it's not done much any more in American comics (which invented them). But you see it in manga times 10. It happens on Teen Titans on Cartoon Network every week. Those big ol' sweat beads that jump off someone's head to indicate to the viewer an emotional state are PLEWDS.

Blurgits: Repetitive motion indicated by drawings that shows arms or legs seeming to be in several places at once in phantom fashion. See: The Flash. Related to speed lines.

Speed lines: Awwww, you know what they are. I[d say the Japanese had made a science of them, except that Carmine Infantino beat them to it."